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/tags/release-0.1-rc2/hive/external/ql/src/java/org/apache/hadoop/hive/ql/lib/NodeProcessor.java

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Java | 44 lines | 7 code | 4 blank | 33 comment | 0 complexity | 97a70d23c6e620fd6561a59ef7feb9ba MD5 | raw file
 1/**
 2 * Licensed to the Apache Software Foundation (ASF) under one
 3 * or more contributor license agreements.  See the NOTICE file
 4 * distributed with this work for additional information
 5 * regarding copyright ownership.  The ASF licenses this file
 6 * to you under the Apache License, Version 2.0 (the
 7 * "License"); you may not use this file except in compliance
 8 * with the License.  You may obtain a copy of the License at
 9 *
10 *     http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18package org.apache.hadoop.hive.ql.lib;
19
20import java.util.Stack;
21
22import org.apache.hadoop.hive.ql.parse.SemanticException;
23
24/**
25 * Base class for processing operators which is no-op. The specific processors
26 * can register their own context with the dispatcher.
27 */
28public interface NodeProcessor {
29
30  /**
31   * Generic process for all ops that don't have specific implementations.
32   * 
33   * @param nd
34   *          operator to process
35   * @param procCtx
36   *          operator processor context
37   * @param nodeOutputs
38   *          A variable argument list of outputs from other nodes in the walk
39   * @return Object to be returned by the process call
40   * @throws SemanticException
41   */
42  Object process(Node nd, Stack<Node> stack, NodeProcessorCtx procCtx,
43      Object... nodeOutputs) throws SemanticException;
44}